3D printing records

This Instructables shows how to 3D print a record. The quality does not match a commercial vinyl disc, but the precision is high enough for the song to be recognised. We already knew how to pirate a vinyl record to make a copy, but you need an original, whereas the printing technique does not.

If you’re interested in knowing how vinyl records were (and still are) made, check out this video.

Source: Adafruit.

Audio Transformers article from Jensen

Here is an extract from the book Handbook for Sound Engineers about audio transformers, from Jensen engineer Bill Whitlock.

Audio Transformers chapter from Handbook for Sound Engineers.


Since the birth of audio electronics, the audio transformer has played an important role. When compared to modern miniaturized electronics, a transformer seems large, heavy, and expensive but it continues to be the most effective solution in many audio applications. The usefulness of a transformer lies in the fact that electrical energy can be transferred from one circuit to another without direct connection, and in the process the energy can be readily changed from one voltage level to another.

MIDI turns 30

Thirty years ago, Dave Smith worked with Roland on a way to make synths and musical instruments communicate. They connected a JP-6 and a Prophet600, and MIDI was born.

Since then, it has been (and still is) at the heart of musical hardware, and even though the technology is behind other means of communications (Bluetooth, WiFi), its presence is still expected. What makes its strength is its simplicity: not much hardware is required, the messages are simple enough to be handled by a small microcontroller (or even discrete logic chips, with a bit of courage), and since it’s not in constant change, there is no need for updates or revisions.

The first MIDI device I made was actually not a musical device. It was an accelerometer-base inclination meter, made for a school project, and we figured out it was a convenient way of transmitting data between the board and the computer, since there was already a program on the other side that can understand the data. Then I started controlling MIDI effects, like the Digitech Whammy, from an Arduino, and that’s when I started developing the MIDI library.

Source: Adafruit & BBC

Ground design considerations on EDN

Here is a series of very interesting articles on how to handle grounding in a PCB design, to avoid hum and EMI, especially when working with both analog and digital (mixed signal) chips.

Other articles in the same topic:

If you’re into electronics and PCB design, check out EDN.com where these articles come from, it’s a real gold mine of information and tips!